What is difference between water cooled chiller and air cooled chiller?

Some chillers need water from cooling tower to cool down condenser those are water cooled chiller

Some chiller have condenser fans and do not need water rather need air to cool down condenser part and are known as air cooled chiller.

the way of how the condenser is cooled 

in water cooled by cooling tower

in air cooled by a fan

the water cooled can be up to2500 tr

The difference between them is that the condenser cooled by water and uses a cooling tower has a wide use in public buildings,  while the chiller which air is used to cool the condenser and is widely used in atomic shelters and some special uses.

The difference between them air chiller is from the fresh air also using refrigerant pipe to put freon but the chilled water is from water cooling to supply cooling both used this in high rise building